The invention is generally directed to a safety device for use in a door opening and closing system of the type which includes an impulse actuated reversible motor for opening and closing the door and in particular to a safety device for use in a garage door opening and closing system of the type which includes an impulse actuated reversible motor which opens and closes the door for automatically actuating the motor for closing the door should the door be inadvertantly opened or accidentally remained open.
Electronic garage door opening and closing systems which are actuated by portable transmitter are well known. Such systems provide the convenience of permitting the garage door to be opened and closed without the physical effort and inconvenience associated with the manual operation for garage doors. They also provide an element of personal safety in that the operator need not leave his car in order to open and close the garage door.
One type of garage door opening and closing system is the impulse type. Impulse type systems require only a short duration electronic signal from the portable transmitter after which the door opener is fully automatic for completely opening or closing the garage door. Because of there convenience in use, such systems are becoming ever increasingly popular.
While such systems have been found to accomplish the purpose of opening and closing garage doors, they are not completely reliable. As with all radio controlled devices, one inherent difficulty is that they will respond to both intentionally or unintentionally produced signals of the required frequency and/or coding. Even though manufacturers have expended great effort to reduce the probability of random openings due to unintentionally produced signals, nevertheless, it is an empirical fact that the probability of such a occurrence exists. With impulse type systems the problem is only aggravated by the fact that only a momentary random signal is necessary in order to actuate the system motor for opening the garage door.
A further aggravating factor related to this general problem is that the garage door openers, on the average, have a cycle time of approximately eight to ten seconds to close the garage doors. Many operators in a hurry to exit their garages activate the system motor with the portable transmitter without waiting to see if the door is fully closed. Should any minor malfunction occur in the system, the garage door will remain partially or totally open.
From a security standpoint, the associated results of a garage door being accidentally opened or inadvertantly remained open may be serious. The seriousness of the consequenses is clear when it is realized that garages are used by homeowners for storing literally thousands of dollars worth of tools and lawn and garden equipment. Also, many garages are attached to homes wherein only a service entrance door separates the garage from the inside of the home. Such service doors are generally totally lacking in security devices so that a garage door left open provides an obvious invitation to both vandalism and burglary.
It is therefore a general object of the present invention to provide a safety device for a door opening and closing system of the type which includes an impulse actuated motor which opens and closes the door.
It is a more particular object of the present invention to provide a safety device for a garage door opening and closing system of the type which includes an impulse actuated reversible motor which opens and closes the door for automaticaly actuating the motor for closing the door should the door be inadvertantly opened or accidentally remained open.
It is a still more particular object of the present invention to provide a safety device for a garage door opening and closing system wherein the safety device may be added to such a system without greatly altering the system.